Twitch response in the canine vocalis muscle
The twitch response of the canine vocalis muscle was investigated through a series of experiments conducted in vitro. Samples of vocalis muscle were dissected and prepared from canine larynges a few minutes before death and kept in Krebs solution at a temperature of 37 ± 1°C and pH of 7.4 ± 0.05. Field stimulation with parallel-plate silver electrodes was applied to study the twitch response of muscle samples. The peak tension and time course of isometric contraction of isolated muscle samples were measured electronically with a Cambridge Technology Dual Servo System (ergometer). Contraction time and 50% relaxation time of this muscle were measured for seven samples at various levels of strain. It was found that contraction time ranged between 22 and 32 ms and 50% relaxation time ranged between 17 and 37 ms. Results indicate that the vocalis muscle is a fast muscle capable of performing rapid maneuvers in support of changes in fundamental frequency.
Alipour-Haghighi, Fariborz, Ingo R. Titze, and Paul Durham. "Twitch response in the canine vocalis muscle." Journal of Speech, Language, and Hearing Research 30, no. 3 (1987): 290-294.
Journal of Speech and Hearing Research